With many liquids, including for example carbonated drinks and wine, when the container is opened the unused or undrunk contents can degrade. For example, carbonated drinks may go flat, whilst wine which has been opened with oxidise. The problem is not only limited to drinks, but may apply to other liquids where contact with air or avoidance of contamination might be desirable. For example, where a liquid is flammable, it may be desirable to fill the remainder of the container with an inert gas to prevent combustion. Where the liquid is, for example, medical use, it would be extremely desirable to prevent contamination.
It is known to keep liquids in containers where the pressure and/or composition of the gas in the head space of the container is appropriately controlled. Thus, it is for example known to keep open bottles of wine under an inert atmosphere and similarly with flammable liquids. However, these have the problem that the gas must be released to dispense the liquid. Similarly, if the pressure in the container is too high then this may cause problems when the liquid is dispensed, for example, by causing a carbonated drink to foam undesirably.
An aim of the present invention is to reduce or overcome one or more of the above problems.